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Realizing the potential of quarkonium

Description: I recall the development of quarkonium quantum mechanics after the discovery of {Upsilon}. I emphasize the empirical approach to determining the force between quarks from the properties of c{anti c} and b{anti b} bound states. I review the application of scaling laws, semiclassical methods, theorems and near-theorems, and inverse- scattering techniques. I look forward to the next quarkonium spectroscopy in the B{sub c} system.
Date: July 1, 1997
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department


Description: It is the purpose of this research to study electrostatic charging mechanisms related to electrostatic beneficiation of coal with the goal of improving models of separation and the design of electrostatic separators. Areas addressed in this technical progress report are (a) electrostatic beneficiation of Pittsburgh #8 coal powders as a function of grind size and processing atmosphere; (b) the use of fluorescent micro-spheres to probe the charge distribution on the surfaces of coal particles; (c) the use of electrostatic beneficiation to recover unburned carbon from flyash; (d) the development of research instruments for investigation of charging properties of coal. Pittsburgh #8 powders were beneficiated as a function of grind size and under three atmosphere conditions: fresh ground in air , after 24 hours of air exposure, or under N2 atmosphere. The feed and processed powders were analyzed by a variety of methods including moisture, ash, total sulfur, and pyritic sulfur content. Mass distribution and cumulative charge of the processed powders were also measured. Fresh ground coal performed the best in electrostatic beneficiation. Results are compared with those of similar studies conducted on Pittsburgh #8 powders last year (April 1, 1997 to September 30, 1997). Polystyrene latex spheres were charged and deposited onto coal particles that had been passed through the electrostatic separator and collected onto insulating filters. The observations suggest bipolar charging of individual particles and patches of charge on the particles which may be associated with particular maceral types or with mineral inclusions. A preliminary investigation was performed on eletrostatic separation of unburned carbon particles from flyash. Approximately 25% of the flyash acquired positive charge in the copper tribocharger. This compares with 75% of fresh ground coal. The negatively charged material had a slightly reduced ash content suggesting some enrichment of carbonaceous material. There was also evidence that the ...
Date: December 1, 1998
Partner: UNT Libraries Government Documents Department

Charged Local Defects in Extended Systems

Description: The conventional approach to treating charged defects in extended systems in first principles calculations is via the supercell approximation using a neutralizing jellium background charge. I explicitly demonstrate shortcomings of this standard approach and discuss the consequences. Errors in the electrostatic potential surface over the volume of a supercell are shown to be comparable to a band gap energy in semiconductor materials, for cell sizes typically used in first principles simulations. I present an alternate method for eliminating the divergence of the Coulomb potential in supercell calculations of charged defects in extended systems that embodies a correct treatment of the electrostatic potential in the local viciniq of the a charged defect, via a mixed boundary condition approach. I present results of first principles calculations of charged vacancies in NaCl that illustrate the importance of polarization effects once an accurate representation of the local potential is obtained. These polarization effects, poorly captured in small supercells, also impact the energetic on the scale of typical band gap energies.
Date: May 25, 1999
Creator: Schultz, Peter A.
Partner: UNT Libraries Government Documents Department

Continuing scearch for a new type charging belt

Description: The EN Tandem accelerator at Oak Ridge National Laboratory (ORNL) operates to support a varied program of atomic physics research. As such, the demands on the accelerator often require a range of operation from {approximately}0.38 to 7.0 MV on the terminal, with low ripple and long term steady state operation. The standard charging belts obtained from the manufacture have generally given acceptable performance, but it is reasonable that modem manufacturing techniques and materials could increase belt lifetimes and improve accelerator performance, particularly voltage ripple. A new belt of significantly different construction from that of the conventional belts was specified, purchased, and installed in 1993. After 2800 hours of use at voltages from 0.38 to 5.8 MV, it was removed from the accelerator in early August 1995.
Date: December 31, 1995
Creator: Jones, N.L.
Partner: UNT Libraries Government Documents Department

3-D Finite Element Analysis of Induction Logging in a Dipping Formation

Description: Electromagnetic induction by a magnetic dipole located above a dipping interface is of relevance to the petroleum well-logging industry. The problem is fully three-dimensional (3-D) when formulated as above, but reduces to an analytically tractable one-dimensional (1-D) problem when cast as a small tilted coil above a horizontal interface. The two problems are related by a simple coordinate rotation. An examination of the induced eddy currents and the electric charge accumulation at the interface help to explain the inductive and polarization effects commonly observed in induction logs from dipping geological formations. The equivalence between the 1-D and 3-D formulations of the problem enables the validation of a previously published finite element solver for 3-D controlled-source electromagnetic induction.
Date: July 20, 2000
Creator: Everett, Mark E.; Badea, Eugene A,; Shen, Liang, C.; Merchant, Gulamabbas A. & Weiss, Chester J.
Partner: UNT Libraries Government Documents Department

Measured environments within 20 meters of the strike points of triggered lightning

Description: Vertical electric fields, azimuthal magnetic fields, and earth voltages developed over 0.5-m radial step distances have been measured at 10 and 20 m from the ground attachment point of triggered lightning. The magnetic fields are found to follow Ampere`s law closely. The relationship between maximum vertical electric field change due to a descending dart leader and the peak of its associated return-stroke current is linear. Recorded earth step voltages have the same waveforms as the incident return-stroke currents, and, for distances between 10 and 20 m from the strike point, their amplitudes exhibit a 1/r dependence. Statistics are given for observed radial filamentary arcing from the ground attachment point.
Date: August 1, 1995
Creator: Fisher, R.J.; Schnetzer, G.H. & Morris, M.E.
Partner: UNT Libraries Government Documents Department


Description: Phase acceptance of the Alternating-Gradient Synchrotron Linear Accelerator is theoretically examined and found to agree well with an experimental determination of phase acceptance. Bunching in the AGS linac is also analyzed, the results indicating a satisfactory understanding of this process also. A double buncher that should be more efficient than the present single buncher is discussed, and space charge effects (as yet unobserved in bunching) are analyzed. (D.C.W.)
Date: March 27, 1963
Creator: Blewett, J.P.
Partner: UNT Libraries Government Documents Department

Search for fractionally charged quarks at ISABELLE

Description: A relatively simple experiment is proposed which is sensitive to conventional quarks of charge 1/3 or 2/3e and mass less than 200 GeV. The experiment uses a modest amount of conventional equipment, no magnetic momentum analysis, and in a period of one week will achieve a sensitivity of 10$sup - 36$cm$sup 2$ to isotropic quark production. Despite the experimental simplicity, the signature provided by a fractionally charged quark should be unambiguous. The method and apparatus are described, background and counting rates are discussed, and finally a cost estimate is given for this experiment. (JFP)
Date: January 1, 1975
Creator: Foley, K.J. & Meadows, B.T.
Partner: UNT Libraries Government Documents Department


Description: Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isospin of the b-quark, and detected the virtual influence of its mate, it became clear that the top quark must exist. Exactly at what mass, we couldn't say, but we knew just how top events would look. We also knew that top events would be rare--if the Tevatron could make them at all--and that picking out the events would pose a real challenge for the experimenters and their detectors.
Date: January 1, 2008
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

Mechanisms for charge-transfer processes at electrode/solid-electrolyte interfaces.

Description: This report summarizes the accomplishments of a Laboratory-Directed Research and Development (LDRD) project focused on developing and applying new x-ray spectroscopies to understand and improve electric charge transfer in electrochemical devices. Our approach studies the device materials as they function at elevated temperature and in the presence of sufficient gas to generate meaningful currents through the device. We developed hardware and methods to allow x-ray photoelectron spectroscopy to be applied under these conditions. We then showed that the approach can measure the local electric potentials of the materials, identify the chemical nature of the electrochemical intermediate reaction species and determine the chemical state of the active materials. When performed simultaneous to traditional impedance-based analysis, the approach provides an unprecedented characterization of an operating electrochemical system.
Date: November 1, 2011
Creator: Chueh, William; El Gabaly Marquez, Farid; Whaley, Josh A.; McCarty, Kevin F.; McDaniel, Anthony H. & Farrow, Roger L.
Partner: UNT Libraries Government Documents Department

Electrostatic Discharge testing of propellants and primers

Description: This report presents the results of testing of selected propellants and primers to Electrostatic Discharge (ESD) characteristic of the human body. It describes the tests and the fixturing built to accommodate loose material (propellants) and the packed energetic material of the primer. The results indicate that all powders passed and some primers, especially the electric primers, failed to pass established requirements which delineate insensitive energetic components. This report details the testing of components and materials to four ESD environments (Standard ESD, Severe ESD, Modified Standard ESD, and Modified Severe ESD). The purpose of this study was to collect data based on the customer requirements as defined in the Sandia Environmental Safety & Health (ES&H) Manual, Chapter 9, and to define static sensitive and insensitive propellants and primers.
Date: February 1, 1994
Creator: Berry, R. B.
Partner: UNT Libraries Government Documents Department

Non-intrusive measurement of particle charge: Electrostatic dry coal cleaning. Technical progress report No. 8, April 1, 1993--June 30, 1993

Description: As we reported in the Technical Progress Report No. 7, there are surges of electric current in the charging loop during triboelectrification of all particles. A high speed data acquisition and analysis system was developed to monitor and record the current pattern. There is no known report on such charge-discharge surges in the literature. The mechanism for it is yet to be understood. The on-line computerized electric current measurement also leads to an observation of charging effects as a function of particle feeding rate. It is shown that feed rate greatly alters particle charge. Such an effect is mostly overlooked by researchers and it could have a important role in process design where the feed rate would be maximized. The initial results for coal and mineral particles demonstrated that the average charge was lower when the feed rate was increased. Further investigation is scheduled to identify potential controlling factors, eg, the solid volume fraction and particle number density could be important process factors. The study of charging velocity and particle size was continued. It was found that particle charge was linearly dependent on the charging velocity for all samples investigated. However, the slope of this linear dependence varied for particles having different diameters. In addition, the charge-velocity relationships were dependent on feeding rates. Hence, the data discussed below include these interrelationships.
Date: September 1, 1993
Partner: UNT Libraries Government Documents Department

An improved search for elementary particles with fractional electric charge

Description: The SLAC Quark Search Group has demonstrated successful operation of a low cost, high mass throughput Millikan apparatus designed to search for fractionally charged particles. About six million silicone oil drops were measured with no evidence of fractional charges. A second experiment is under construction with 100 times greater throughput which will utilize optimized search fluids.
Date: August 1, 1996
Creator: Lee, E.R.
Partner: UNT Libraries Government Documents Department


Description: CPT invariance is a fundamental property of quantum field theories in flat space-time. Principal consequences include the predictions that particles and their antiparticles have equal masses and lifetimes, and equal and opposite electric charges and magnetic moments. It also follows that the fine structure, hyperfine structure, and Lamb shifts of matter and antimatter bound systems should be identical. It is proposed to generate new stringent tests of CPT using precision spectroscopy on antihydrogen atoms. An experiment to produce antihydrogen at rest has been approved for running at the Antiproton Decelerator (AD) at CERN. We describe the fundamental features of this experiment and the experimental approach to the first phase of the program, the formation and identification of low energy antihydrogen.
Date: November 1, 2000
Partner: UNT Libraries Government Documents Department

Properties of electrostatically-driven granular medium: Phase transitions and charge transfer

Description: The experimental and theoretical study of electrostatically driven granular material are reported. It is shown that the charged granular medium undergoes a hysteretic first order phase transition from the immobile condensed state (granular solid) to a fluidized dilated state (granular gas) with a changing applied electric field. In addition a spontaneous precipitation of dense clusters from the gas phase and subsequent coarsening--coagulation of these clusters is observed. Molecular dynamics simulations shows qualitative agreement with experimental results.
Date: October 14, 1999
Creator: Aranson, I. S.; Kalatsky, V. A.; Crabtree, G. W.; Kwok, W.-K.; Vinokur, V. M. & Welp, U.
Partner: UNT Libraries Government Documents Department

Flow induced charging of liquids in reduced gravity

Description: Microgravity experiments on free fluid surfaces of large length scale could be subject to experimental artifact from flow induced charging. Under conditions favorable for flow induced charging, flowing liquids develop a static electrical charge which manifests itself as a force whose magnitude approaches that of surface tension force. Favorable conditions are: a non-conducting liquid, a small diameter non-conducting flow passage, a large flow volume, and a small separation distance between the fluid and another object. We present a method for calculating the magnitude of flow induced charging and scaling arguments so that potential problems can be determined and dealt with at the experimental design phase. A dimensionless ratio of charge force to surface tension force we call the Hula Number should be less than 0.5 to prevent artifact or unwanted fluid motion.
Date: February 1, 1996
Creator: Pettit, D.R.
Partner: UNT Libraries Government Documents Department